In the farming industry, feed is often delivered to the animals by liquid feeding systems. This causes several problems. Potential harmful bacteria and organisms are natural inhabitants of soil and vegetation and are accordingly found on feed components and everywhere in the animal's surroundings. The bacteria and other organisms present will ferment, unless prevented e.g. by sterilization. The fermentation may result in outgrow of pathogenic bacteria e.g. Vibrio spp., Campylobacter spp., Salmonella spp., E. coli, and Stapholococcus aureus. Furthermore, there might be a high content of various types of yeast and molds. This uncontrolled growth in the liquid feed may result in illness, malnutrition, diarrhea, or even death of the animals. Furthermore, animals infected with Campylobacter spp. or Salmonella spp. may transfer the infection to humans, and therefore it is desirable to avoid such infections in animals.
Production of a fermented mixed feed in an environment with high microbial pressure, including pathogenic microorganisms is very challenging, and many attempts have failed so far. Generally, conventional inoculation of feed with starter cultures requires cultivation and propagation steps, including a sterile handling of bacteria. This is highly challenging for a farmer, who is not trained in general microbiological skills, and who is surrounded by an environment of high microbial pressure, such as found in conventional feeding kitchens in a pig farm. The alternative, a “continuous” fermentation, where a portion of the fermented feed is used as inoculum for a new fermentation batch, suffers from gradual increase of undesired microorganisms, such as acid tolerant yeasts. These are not only known to have a detrimental effect on the fermented feed, but they can be very difficult to get rid off, especially in the feeding pipes.
It has proven very difficult, if not impossible, to avoid the above-mentioned problems if liquid feed is to be used as feed. Accordingly, the use of dry feed is often the alternative choice.
Until recently, antibiotic-based growth promoters were provided to e.g. pigs on a routine basis, in order to prevent e.g. diarrhea, and thereby to increase weight gain (hence the term “growth promoter”). The use of antibiotic-based growth promoters by farmers has been banned in several countries, including EU. This is in part caused by the fear of generating multi-resistant pathogenic microorganisms. However, use of antibiotics has not stopped, and veterinarians prescribe antibiotics for treatment of large numbers of pigs every day.
By the present invention, the above-mentioned problems have been solved. Furthermore, the invention provides a non-antibiotic growth promoter.